This invention relates to aircraft emergency evacuation systems employing an inflatable escape slide and more particularly to methods and apparatus for stowing and automatically deploying the inflatable escape slide of such a system.
Emergency evacuation systems that employ inflatable escape slides are installed on virtually all passenger carrying aircraft to provide rapid evacuation of the passengers and crew during on-ground emergencies such as those following an emergency landing or a ditching at sea. During normal aircraft operation, the deflated escape slide is generally packed in a compact package or container that is mounted on the interior surface of the aircraft door or on the floor of the aircraft at a position adjacent the door. In most systems, the upper end of the escape slide includes a girt which encompasses a girt bar that is connected to the aircraft floor at a position immediately inside the door. In the event of an emergency, the door is opened and the escape slide is automatically or manually urged through the doorway and inflated so as to form a slide that extends downwardly from the door sill to the surface of the ground or water.
It can be readily recognized and is well known in the art that numerous design and manufacturing constraints apply to emergency evacuations of the above-described type. For example, the system should be capable of rapid actuation and deployment of facilitate speedy evacuation of the aircraft. Generally, this requires an automatic deployment sequence that is initiated by simply actuating the aircraft door, or by some other simple operation that is easily implemented by a passenger or crew member. To permit use of the door during nonemergency conditions, an arming and disarming device must be provided and, in systems wherein the container or pack containing the deflated slide is not attached to the interior of the aircraft door, means must generally be provided to facilitate movement of the stowed escape slide so as to provide access to the door when the escape slide is not needed.
In addition, various types of doors are employed in modern aircraft and the evacuation system often must be either specifically configured for a particular type of door or must be adapted thereto. For example, in prior art evacuation systems that operate in conjunction with a plug-type door of the variety wherein the door is opened by moving it outwardly and then longitudinally in a direction that is generally parallel to the outside of the aircraft, prior art proposals have included arrangements wherein the stowed evacuation system is positioned adjacent the door so as to be available should an emergency condition develop and proposals wherein the deflated slide is stowed within the lower portion of the door and ejected therefrom as the door is moved outwardly during an emergency evacuation procedure. On the other hand, in the more preferred arrangements for use with overhead doors, the stowed evacuation system is attached to the interior of the door and moves upwardly with the door when it is opened under normal, nonemergency conditions. With this type of arrangement, the stowed evacuation system remains attached to the aircraft floor by means of a girt bar or other fastening arrangement when such an overhead door is moved upwardly for emergency evacuation. As the door reaches a predetermined height, the stowed evacuation system is either forcibly ejected or falls from the door under the force of gravity and the escape slide is inflated by means of aspirators or turbine-type air pumps. In each of these systems, the girt bar usually must be rocked into place in front of the aircraft door to arm the evacuation system and must be disconnected therefrom so that the door can be utilized without deploying the escape slide. Additionally, such system may or may not be usable with or adaptable to various other types of doors such as the upwardly and outwardly swinging emergency door of the type that presently is used with the hereinafter disclosed embodiment of this invention.
Because of the above-mentioned constraints, prior art evacuation systems have often been more complex than desired, requiring, for example, relatively long hoses for interconnecting the inflatable escape slide with a supply of compressed air that is located within the aircraft and relatively complex actuation arrangements for activating the gas supply at a proper time within the system deployment sequence. Further, to stabilize the inflated slide with respect to substantial winds and other environmental forces that could interfere with deployment and use of the system, prior art systems have sometimes required various automatic engagement or hold-down devices that secure portions of the deployment system to the exterior of the aircraft as the inflatable slide is deployed and inflated. Such devices as well as other complex mounting or track arrangements which can be required to facilitate the movement of the deflated, stowed system from a deployable position in front of the door to a position that provides access to the door under nonemergency conditions, have often increased the overall system complexity.
Even further, the prior art systems have been subject to a number of less critical disadvantages and drawbacks. For example, in most systems, the girt bar and its mounting brackets project upwardly from the floor of the aircraft so that a certain degree of care must be exercised as the passengers and crew leave the aircraft. Moreover, in most prior art arrangements, various system components are mounted to the aircraft with the inflatable slide and the remaining portions of the deployment system being packed in or forming the container that is ejected through the aircraft door. Although such a configuration can be satisfactory under some conditions, it is generally more desirable if the evacuation system is arranged as a single unit that can be preassembled and easily installed in the aircraft. Additionally, prior art systems have often required the use of special tools and procedures in order to properly pack the deflated escape slide within the system container or stowage arrangement with minimal risk of damage.
Each of the above-mentioned design constraints becomes even more imposing relative to evacuation systems for large transport aircraft, especially passenger carrying aircraft of the type having both upper and lower passenger decks. In particular, the doors which provide normal and emergency access to (and egress from) the upper deck region of such an aircraft are located a considerable distance from the surface of the ground when the aircraft is fully supported by its landing gear. In emergency landing situations, the normal and emergency exits of the upper deck region can be at a substantially higher elevation if the aircraft comes to rest in a nose-up or in an opposite wing-down attitude. Since it is desirable and necessary to provide for evacuation of the upper deck region regardless of the attitude of the aircraft, a comparatively long escape slide must be utilized. This, of course, reflects on and complicates the above-mentioned problems of satisfactorily stowing and rapidly deploying the escape slide. Moreover, further complications arise in situations wherein an upper deck region is configured to carry a relatively large number of passengers and it is desired or necessary to hide an escape slide of sufficient width to allow two passengers or crew members to descend alongside of one another.
It is therefore a general object of this invention to provide an emergency evacuation system of minimal complexity wherein the inflatable escape slide and all components of the associated deployment mechanism are contained in a single unit that can be readily installed in and removed from an aircraft.
It is another object of this invention to provide an aircraft emergency evacuation system which is suitable for use with and facilitates relatively long and relatively wide inflatable escape slides that are suitable for evacuating the upper deck region of a large transport aircraft.
It is a still further object of this invention to provide an aircraft emergency evacuation system wherein a relatively large escape slide is automatically deployed as an upwardly and outwardly swinging aircraft escape door is actuated and wherein the entire evacuation system forms a single unit that is stowed along the lower portion of the interior surface of the escape door.
Even further, it is an object of this invention to provide an emergency evacuation system of the above-mentioned type wherein rapid and reliable deployment of an inflatable escape slide is attained without the need for and use of devices that automatically secure the deployed escape slide to the exterior surface of the aircraft.
Moreover, it is an object of this invention to provide such an emergency evacuation system wherein the system is easily armed and disarmed without separate engagement or disengagement of the system girt bar with the aircraft floor and wherein the girt bar does not project upwardly from the aircraft floor during emergency evacuation procedures.